ROI-Guided CT Scanning With Dynamic Collimation Control

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Solution Overview

Problem

Existing CT imaging and image-guided radiation therapy (IGRT) systems struggle to effectively focus high-energy x-ray beams on tumor regions while minimizing exposure to surrounding tissues, leading to inefficiencies and potential harm to non-target areas.

Innovation Solution

A system and method that utilizes region of interest (ROI) data to optimize CT scanning by integrating low-energy kV and high-energy MV radiation sources, employing a rotatable gantry with synchronized patient movement, and dynamic collimation to control radiation exposure based on ROI parameters, enhancing image quality and reducing scatter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional CT imaging is used to image the entire patient body, then complete anatomical coverage is achieved, but radiation exposure to non-target areas increases and scan time extends

Engineering Contradiction:
Improveradiation exposure to non-target areasVSAvoidimaged area coverage
Core Design Contradiction:
Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent segments the imaging process into two distinct phases: a preliminary low-dose CT scan to identify the region of interest (ROI), followed by a high-dose focused scan only on the identified ROI. This segmentation allows the system to avoid exposing non-target areas to high-dose radiation while ensuring complete coverage of the tumor region, directly resolving the contradiction between reducing radiation exposure and maintaining adequate imaging coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using dynamic collimation to concentrate high-dose radiation precisely on the identified ROI while minimizing exposure to surrounding tissues. The collimation system adjusts the radiation beam shape and intensity locally based on the ROI characteristics, ensuring that high-dose areas are restricted only to where diagnostic information is most needed, thus reducing overall radiation exposure while maintaining imaging effectiveness.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If high-dose radiation is used to improve image quality in the region of interest, then diagnostic precision increases, but radiation exposure to surrounding tissues increases

Engineering Contradiction:
Improveimage quality in ROIVSAvoidradiation exposure to surrounding tissues
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements local quality by using dynamic collimation to concentrate high-dose radiation precisely on the identified ROI while minimizing exposure to surrounding tissues. The collimation system adjusts the radiation beam shape and intensity locally based on the ROI characteristics, ensuring that high-dose areas are restricted only to where diagnostic information is most needed, thus reducing overall radiation exposure while maintaining imaging effectiveness.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent performs a preliminary low-dose CT scan before the high-dose focused scan to identify and delineate the ROI boundaries. This preliminary action allows the system to plan the subsequent high-dose scan parameters (collimation, beam angle, intensity) to precisely target only the necessary areas, preventing unnecessary radiation exposure to surrounding tissues while ensuring adequate image quality in the ROI.

Inventive Principle:
Principle #10Preliminary action

3Loss of information

If a comprehensive CT scan of the entire patient is performed, then all anatomical structures are visualized, but scan time increases

Engineering Contradiction:
Improveanatomical information coverageVSAvoidscan time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The patent segments the imaging process into two distinct phases: a preliminary low-dose CT scan to identify the region of interest (ROI), followed by a high-dose focused scan only on the identified ROI. This segmentation allows the system to avoid exposing non-target areas to high-dose radiation while ensuring complete coverage of the tumor region, directly resolving the contradiction between reducing radiation exposure and maintaining adequate imaging coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by performing a comprehensive scan only when necessary (during the preliminary phase) and using focused partial scans for the main diagnostic purpose. The system determines that a full comprehensive high-dose scan is excessive when a preliminary scan has already identified the ROI, allowing the procedure to stop at partial scanning while still achieving the diagnostic goal, thus reducing scan time without losing critical anatomical information.

Inventive Principle:
Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables targeted radiation exposure, reducing scan time, minimizing exposure to non-target areas, and improving image quality, thus enhancing the precision and safety of image-guided radiation therapy.

Implementation Method 1

exposing a patient or a portion of a patient to a radiation source and positioning a radiation detector to receive x-ray radiation from the radiation source

Methodology Applied
Scientific EffectX-ray radiation: X-Ray

Implementation Method 2

positioning a radiation detector to receive x-ray radiation from the radiation source

Methodology Applied
Scientific EffectX-ray detection: X-Ray

Implementation Method 3

Computed tomography (CT) imaging generally involves exposing a patient or a portion of a patient to a radiation source

Methodology Applied
Scientific EffectComputed tomography: Tomography

Data Source

PatentEP3886711B1Optimized scanning methods and tomography system using region of interest data
Publication Date: 2025.07.02 ACCURAY LLC
  • EP3886711B1 patent drawingFigure 1
  • EP3886711B1 patent drawingFigure 2
  • EP3886711B1 patent drawingFigure 3

AI summary

A method of scanning parameter optimization, which method may be useful with image-guided radiation therapy (IGRT), allows for controlling exposure of a beam from an x-ray source and/or controlling the detection mechanism for an x-ray detector of imaging radiation of a radiation-delivery device based on one or more parameters of a region of interest of a patient. The one or more parameters of the region of interest may include a dimension, outer contour, density, location relative to an outlet of the beam, location relative to isocenter, location to the whole patient body, etc. Exposure of the patient to the beam may be varied via modulation of one or more scanning parameters for controlling an aspect of the beam and/or the detector to provide for targeted and or reduced radiation exposure of the patient or portion of the patient, and/or for improved quality of guiding images. The modulation may be varied depending on a view angle of the region of interest from a portion of the radiation-delivery device.